Biomass energy utilization in rural areas may contribute to alleviating energy crisis and global warming: A case study in a typical agro-village of Shandong, China

摘要

A biomass energy exploration experiment was conducted in Jiangjiazhuang, a typical agro-village in Shandong, China from 2005 to 2009. The route of this study was designed as an agricultural circulation as: crops →crop residues → "Bread" forage → cattle →cattle dung → biogas digester → biogas/digester residues → green fertilizers → crops. About 738.8 tons of crop residues are produced in this village each year. In 2005, only two cattle were fed in this village and 1.1% of the crop residues were used as forage. About 38.5% crop residues were used for livelihood energy, 24.5% were discarded and 29.7% were directly burned in the field. Not more than three biogas digesters were built and merely 2250 m~3 biogas was produced a year relative to saving 1.6 tons standard coal and equivalent to reducing 4.3 tons CO_2 emission. A total of US$ 4491 profits were obtained from cattle benefit, reducing fossil energies/chemical fertilizer application and increasing crop yield. After 5 years experiment, cattle capita had raised gradually up to 146 and some 62.3% crop residues were used as forage. The percentages used as livelihood energy, discarded and burned in the field decreased to 16.3%, 9.2% and 9.8%, respectively. Biogas digesters increased to 123 and 92,250 m~3 biogas was fermented equal to saving 65.9 tons standard coal and reducing 177.9 tons CO_2 emission. In total US$ 60,710 profits were obtained in 2009. In addition, about 989.9 tons green fertilizers were produced from biogas digesters and applied in croplands. The results suggested that livestock and biogas projects were promising strategies to consume the redundant agricultural residues, offer livelihood energy and increase the villagers' incomes. Biogas production and utilization could effectively alleviate energy crisis and CO_2 emission, which might be a great contribution to reach the affirmatory carbon emission goal of the Chinese government on Climate Conference in Copenhagen in 2009.